Separation apparatus



June 27, 1939. D. M. WRIGHT SEPARATION APPARATUS Filed April 25, 1937David M Wrzyfi t ATTEST- I NVENTOR ATTORN EY Patented June 27, 1939UNITED STATES SEPARATION APPARATUS David M. Wright, Agricola,

dustrial Patents Corp corporation of Delaw Application April 23, 1

6 Claims.

This invention relates to ap for usein recovering phosphatic materials.

Specifically, the present invention is an'improvement on the separationapparatus described 5 and claimed in United States Letters Patent No.

paration apparatus to George 2,006,471 entitled Se H. McCoy, David M.Wright, and Jesse Pankey Hall. The separation apparatus of United StatesPatent No. 2,006,471 includes a receptacle, means for maintainingsubstantially a constant level of water in the receptacle, andangula'rly disposed under water screens employed to effect a separationbetween agglomerated phosphate fines and silica, the silica passingthrough the screens and the phosphatic agglomerates passing over thescreens, being separately withdrawn at the bottom.

In preparing phosphate bearing fines for treatment in accordance withthe teachings of. United States Patent No. 2,017,468 granted on theapplication of the same inventors as of United States Patent No.2,006,471, the phosphate fines are selectively oiled to formagglomerates. After the initial screening operation by which the largeror pebble size particles of rock phosphate are recovered in accordancewith usual practice, the fine portion of the mined material is subjectedto a washing operation, during which a large portion of the dirt, sand,and other foreign material is removed. The remaining washed materialwhich is a mixture of sand and rock phosphate of about equal size, isthen conveyed to a mixer, where it is mixed with an agglomeratingsubstance. The 35 agglomerating substance may be of any suitable kind,it being necessary, however, that the material have the joint propertiesof, first, an affinity for the rock phosphate and not the sandparticles, and, secondly, when applied to the rock 40 phosphateparticles, to cause such particles to adhere together by agglomeration,forming the smaller particles of rock phosphate into agglomerates, for apurpose hereinafter more specifically set forth.

. Agglomeration is normal] sion of soap and oil. Suitable materials areany kind of cheap mineral oil, such as fuel oil, and any fatty acid orrosin soap, preferably the former, of a cheap grade. These products areemulsified in a suitable apparatus with a small quantity of water, whichis added thereto.

After the mixing process referred to, it will be found that the rockphosphate particles are'agglomerated and exist in larger physical formthan the particles of sand. The mixture is then fed forwardly anddeposited onto an apparatus which is effective to mechanically separatethe particles on the basis of their size, as by passing over a screenwhich will permit the smaller sand particles to fall through and thelarger agglomerated y effected by an emulparatus adapted particles ofFla., assignor to Inoration, Chicago, 111., a

are

937, Serial No. 138,671

rock phosphate to pass over the screen.

In further practicing the process, after an initial separation has beenaccomplished as above described, the agglomerated particles may be againmixed and broken up and allowed to aggomerate a second time, all for thepurpose of freeing any particles of sand or other impurities which mayhave been entrapped in the agglomerated particles in the first instance.After this operation, a second separation may be effected in the samemanner, such as by passing over a sec ond screen. This second step, is arefinement process and makes for a more purified final prodnot. Afterthe above described separating action, the sand and other impurities maybe discarded and the agglomerated phosphatic material collected andprepared for further treatment.

I have found that when the treated material is fed to the screen, muchof the fine sand tends to surge forward in the water and remain insuspension above the screen, settling by gravity near the discharge endof the tank on top of phosphate material about to be discharged. Thisresults in this sand being included with the recovered phosphate insteadof passing through the screen. The present invention provides anapparatus to prevent this behavior of the sand.

The invention will be readily understood by reference to the drawing,which is a diagrammatic representation of the separation apparatus ofthe present invention.

The separator of the present invention comprises a tank I, which ispreferably of the construction shown, namely, of a general triangularshape in cross section having an inclined bottom 2. 'The .tank isprovided with an inclined stationaryscreen 3 spaced above the floor 2.Screen 3 is appropriately mounted and terminates at its bottom end atwall 4. Inclined guard plate 5 is mounted above and in spaced,substantially parallel relationship with screen 3 and sufiiciently closeto screen 3 to prevent the material being screened from surging throughthe body of liquid contained in tank I. The guard plate 5 is extendedsubstantially over the entire screening area of screen 3 and at itslower end 6, terminates below wall 4. Inclined baffle plate I! is fittedat the bottom of the tank as shown, having the same inclination asscreen 3. Inclined bafiie plate 1 terminates at its end 8 at a pointbelow wall 4, providing an opening between end 8 and wall 4, whichopening is above the lower end 60f guard plate 5. Partition 9 is spacedfrom the end of the tank I. Pipe II is provided to supply water, whichis preferably maintained at the level indicated by dotted line I 2 andoverflows through overflow pipe l3.

Obviously, the guard plate may be terminated at its upper edge at theline of introduction of the material whether that line be above or belowthe liquid level II.

The treated phosphate feed enters the tank at the upper end of screen 3and passes down over screen 3. The fine sand, which tends to rise in theform of a cloud above screen 3, is restrained by guard plate 5, and muchof it returned to the screen surface to pass therethrough. The sandpassing through the screen is removed through outlet II. The phosphaterock agglomerates, being larger in size than the screen mesh, pass overscreen 3 and pass by gravity through the space between wall 4 and baflleplate I to be withdrawn through outlet l5. Such sand as remains insuspension above screen 3 at the time the material passes over the topof wall 4 continues above baffle plate I and may be withdrawn throughoutlet Ill.

The apparatus of the present invention permits the production ofphosphate rock agglomerates unusually free from sand since the lightersand which normally does not pass through the screen in under waterscreening work is trapped by baflle plate I and prevented fromaccumulating with the agglomerates at the bottom of the tank.

Wall 4 obviously is provided to form a barrier for sand which passesthrough screen 3.

It will be understood that the present invention is not limited to theembodiment disclosed in the drawing, but is to be construed broadly asdefined in the claims which follow.

I claim:

1. In an under-liquid screening device including a, liquid receptacleand means for maintaining a body of liquid in the receptacle at apredetermined level, an angularly disposed screen mounted within thereceptacle and below the liquid level, a guard plate mounted above thescreen and in substantially parallel relationship therewith, the guardplate being extended substantially over the entire area of the screenand to the liquid level and sufiiciently close to the screen to preventmaterial to be screened from surging through the body of liquid and anopening permitting passage of the body of liquid to either side of theguard plate at a point below the lower limit oi the screen.

2. In an under-liquid screening device including a liquid receptacle andmeans for maintaining a body of liquid in the receptacle at apredetermined level, an angularly disposed screen mounted within thereceptacle and below the liquid level, the'screen being terminated shortof one wall of the receptacle, a guard plate mounted above the screenand in substantially parallel relationship therewith, the guard platebeing extended substantially over the entire area of the screen, to theliquid level and relatively close to the screen and adapted to preventmaterial to be screened from surging through the body of liquid, anopening permitting passage of the body of liquid to either side of theguard plate at a point below the lower limit of the screen and a battleplate extending from said wall of the receptacle and terminating shortof the screen.

3. In an under-liquid screening device including a liquid receptacle andmeans for maintaining a body of liquid in the receptacle at apredetermined level, an angularly disposed screen mounted within thereceptacle and below the liquid level, the screen being terminated shortof one wall of the receptacle, a guard plate mounted above the screenand in substantially parallel relationship therewith, the guard platebeing extended substantially over the entire area of the screen, to theliquid level and relatively close to the screen and adapted to preventmaterial to be screened from surging through the body of liquid, anopening permitting passage of the body of liquid to either side of theguard plate at a point below the lower limit of the screen and a baflleplate extending from said wall of the receptacle and terminating shortof the screen, the ballie plate being extended in substantially the sameplane as the screen.

4. In an under-liquid screening device includ ing a. liquid receptacleand means for maintaining a body of liquid in the receptacle at apredetermined level, an angularly disposed screen mounted within thereceptacle and below the liquid level, the screen being terminated shortof one wall of the receptacle, a guard plate mounted above the screenand in substantially parallel relationship therewith, the guard platebeing extended substantially over the entire area of the screen, to theliquid level and relatively. close to the screen and adapted to preventmaterial to be screened from surging through the body of liquid, anopening permitting passage of the body of liquid to either side of; theguard plate at a point below the lower limit of the screen, a baffleplate extending from said wail of the receptacle and terminating shortof the screen, the baflie plate extended in substantially the same planeas the screen, means for removing material passed over the screen andbeneath the baiile plate and means for removing material passed abovethe baflle plate.

5. In an under-liquid screening device including a liquid receptaclehaving an inclined bottom and substantially vertical side and end walls,and means for maintaining a body of liquid in the receptacle at apredetermined level, an angularly disposed screen spaced above thebottom and below the liquid level, the screen being terminated short ofthe end wall, a guard, plate mounted above the screen and insubstantially parallel relationship therewith, the guard plate beingextended substantially over the entire area of the screen, to the liquidlevel and relatively close to the screen and adapted to prevent materialto be screened from surging through the body of liquid, an openingpermitting passage of the body of liquid to either side of the guardplate at a point below the lower limit of the screen and a baille plateextending from the end wall and terminated short of the screen, thebaffle plate being extended in substantially the same plane l as thescreen.

6. In an under-liquid screening device including a liquid receptacle andmeans for maintaining a body of liquid in the receptacle at apredetermined level, an angularly disposed screen mounted within thereceptacle and below the liquid level, a guard plate mounted above thescreen and in substantially parallel relationship therewith, the guardplate being extended substantially over the entire area of the screenand to the line of introduction of material to the screen andsufficiently close to the screen to prevent the material from surgingthrough the body of liquid and an opening permitting passage of the bodyof liquid to either side of the guard plate at a point below the lowerlimit of CERTIFICATE OF CORRECTION.

Patent No. 2,165,927. June 27, 19 9.

DAVID M. WRIGHT It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows: Pagel, sec- 0nd column, line 1;.8,for the reference numeral"17" read 7; page 2, first column, line 18, for "15" read 16; and thatthe said Letters Patent shouldbe read with this correction therein thatthe same may conform to the re'c- 0rd of the case in the Patent 0ffi-ce.

Signed and sealed this 15th day of August, A. D. 1959.

Leslie Frazer (Seal) Acting Commissioner of Patents.

